Equipment manufacturers supplying specialist equipment into the process industries for use where flammable liquids, gases or dusts are handled have responsibilities for the safety and suitability of their equipment under European single market legislation specifically directive 94/9/EC. Operators of process plants handling flammables have responsibilities under European harmonised health and safety law, specifically directive 99/92/EC. The legal responsibilities of those who design and build such plants, who are likely to be neither an equipment manufacturer nor the final plant operator are quite unclear, unless that plant comes under the major hazards directive 96/82/EC (Seveso 2). This paper describes some examples where the uncertainty has contributed to bad design and serious consequences, and suggests questions the design contractor and final user need to address to minimise these problems. (c) 2007 Elsevier Ltd. All rights reserved.